Chechen leader Ramzan Kadyrov on Thursday ordered his troops to "shoot to kill" if they encountered any unauthorised Russian forces on the territory of the small republic in the volatile North Caucasus region.

All carry-on liquids will be banned at Moscow`s three international airports ahead of next month`s Winter Olympics in Sochi for security concern, the Russian flight authority posted the decision Wednesday.

A female suicide bomber attacked a bus in southern Russia on Monday, authorities said, killing at least six people in the deadliest such blast outside the volatile North Caucasus region in nearly three years.